Projectile for firing a leakproof caseless round



Feb. 16, 1965 J. J. SCANLON, JR

PROJECTILE FOR FIRING A LEAKPROOF CASELESS ROUND 2 Sheets-Sheet 1 Filed June 14, 1963 M \k m IN VENTOR J SCAN LON JR BY:

if. aw M iPM ATTORNEY- Feb. 16, 1965 J. SCANLON, JR

PROJEICTILE FOR FIRING A LEAKPROOF CASELESS ROUND 2 Sheets-Sheet 2 Filed June 14, 1963 m if y 2 AX? ///w[ m VVVM VMV INVENTOR.

JOHN J. SCANLON JR BY-X/ %2% 2 PM ATTORNEY? United States Patent 3,169,333 PROJECTILE FOR FIRING A LEAKPRQOF CASELESS ROUND John J. Scanlon, Jr., Levittown, N.J., assignor. to the United States of America as represented by the Secretary of the Army Filed June 14, 1963, Ser. No. 288,057

. 4 Claims. (Cl. 42-69) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty there- This invention relates to a projectile located .in rear of a caseless round of propellant for firing another pro jectile in front of such a round in a gun barrel. An object is to'provide aninexpensive improved method and apparatus for firing a caseless round of propellant in small arms and other weapons having no obturating pad in a breech closure where such weapon may have been intended for'use with ammunition having a metal cartridge case.

In a round having propellant in a usual metal case, on being fired the case expands under internal gas pressure due to combustion of the propellant, sufficiently to force the cylindrical case walls so tightly against the wall or the chamber or barrel of the gun in which fired that rear leakage of gas past the breech closure has been no problem. With the advent of recoilless guns in many calibers, the trend has been toward lightness in weight not only of the gun but also of ammunition. In recoilless weapons rear leakage of gas is a necessity and the use of caseless rounds has been no problem. However in small arms and other sizes designed for use with metal cases of propellant, the breech block, bolt, or other closure has not previously been provided with an obturating pad as have the artillery weapons intended for separate loading ammunition. It is in weapons of this last class that the advantages of lightness in weight from the use of caseless rounds of propellant is used. Perhaps the largest class of weapons so barred from being supplied with caseless, lighter weight rounds of ammunition are the infantrys 30 and 50 caliber rifles, of which there are literally millions in existence today. This invention may therefore be viewed as lightening the weight of ammunition each infantryman has to carry by eliminating for him the weight of all the metal cartridge cases he has had to transport. Viewed in another way it has enabled the infantry to be more effective by-each individual soldier being able to shoulder more rounds.

Referring to the drawings:

FIG. 1 shows the two projectiles with a caseless propellant between them,

FIG. 2 shows a longitudinal section through a projectile before it has been inserted in the firing chamber of a gun,

FIG. 3 is a view corresponding to FIG. 1 but in which an electric instead of a percussion primer is used,

FIG. 4 is a detail showing the O ring in the rear projectile of FIGS. 1 and 3 distorted by propellant pressure,

FIG. 5 shows the 0 ring before the projectile carrying it has been inserted in the firing chamber of a gun,

FIG. 6 illustrates the shape of the O ring before the application of propellant pressure but after it has been inserted in the gun.

As shown in FIG. 1 the bolt breech closure 8 of a caliber rifle containsthe usual axially disposed firing pin 7 for percussion operation of the usual fixed ammunition round containing a metal case not shown. The gun barrel 9 may be the usual one or when made especially for the two projectiles illustrated may have the rifling begin further forward and under the front projectile 10a. Each projectile is provided with a jacket 11 of brass or any other commonly used jacket material provided with grooves in which are located 0 rings 12 for the purpose of preventing propellant pressure from the caseless round between these projectiles from leaking rearwardly through the bolt 8 or around it. Each of the projectiles 10 and 10a has a firing rod or pin 13 freely slidable longitudinally through it with an enlarged rear end. A spring 14 cooperates with enlarged rear end of firing rod 13 and with a body portion of the projectile. A caseless propellant 15 lies between the two projectiles mentioned. An obturating cup 16 of deformableprimer cup material is secured in an end of the projectile body by a forced fit or otherwise. The base of cup 16 is deformable by impact from the firing pin 7 to the shape 17 shown in the forward projectile. The caseless round 15 is provided in its rear portion with a primer composition 18 and a more sensitive percussion responsive cap 19 capable of firing the primer and propellant when struck by the pointed front end of the firing rid 13 of the rear projectile 10. The front tapered end 20 of projectile 1t) fits within a correspondingly tapered rear center of the caseless round 15 to allow the firing rod 13 of the rear projectile when struck by the firing pin 7 to be forced forward igniting the cap 19, primer 18, and caseless propellant 15, firing the forward projectile 10a out of the gun without danger of gas leakage rearwardly. After the base of cup 16 has been deformed as shown in FIG. 1 for the forward projectile the rod 13 may project from the body of the projectile. This may enhance the lethality of projectile 10a by causing it to tumble or turn within the body of the game being hunted.

In operation, after the propellant 15 has been fired and the leading projectile 19a has left the muzzle of the gun, another caseless round is next inserted pushing the formerly rear projectile forwardly. Then a rear projectile is inserted pushing both the leading projectile and its propellant forwardly. After that the bolt or breech closure is moved forward into firing position ready to receive impact from the firing pin 7 of the bolt. To facilitate loading, a stilt thin walled plastic capable of rapid burning may enclose the propellant 15 and forward portion of projectile 10 down to the leading O ring to save time and enable both of them to be inserted as a unit instead of separately. This stiff consumable plastic may or may not conform to the contour of forward taper in the rear projectile.

In FIG. 2 is shown the projectile 10 before being inserted to push the propellant and leading projectile forward. As is herein shown the firing rod 13 projects only very slightly from the projectile nose. Instead of the base of cup 16 being stitf enough to hold spring 14 compressed and the point of rod 13 projecting as shown in FIG. 1, the base of cup 16 may be made thin enough to allow the rod 13 to fire a propellant round but yet the spring 14 strong enough to return the thin base to its former position or bulging rearward slightly, which should not be objectionable where the rod 13 is not desired to project from the forward projectile as in FIG. 1. When the projectile is in the rear FIG. 1 position the base of cup 16 must be strong enough to withstand propellant pressure tending to rupture it. Another expedient is to have the base of cup 16 strong enough to function as a toggle, i.e., the disc being prestressed to have a bulge either outward or inward but never capable of being fiat and without any bulge. This cup base may bulge outward by firing pin 7 to move rod 13 and fire propellant and then be bulged back by propellant pressure, where the o a rod 13 is not desired to be extended out of the projectile when fired.

In FIG. 3 is exemplified a construction whereby the rear projectile and its firing rod may electrically fire the caseless propellant 15 by means of an electric current passed through firing pins 7a, 13a instead of firing such propellant through percussion mechanism. In this embodiment the rods 7a and 13a need have no longitudinal movement and no helical spring 14 but insulation around these rods or pins is needed. After passing the cap 19a and primer 1841 the electric current returns to its source through a suitable ground connection. In FIG. 3 the firing rod 13:; needs to extend out from the body of the projectile as shown and is not adapted to be withdrawn as mentioned under FIG. 1.

FIG. 4 shows a section through the 0 ring at a. time when deformed under propellant pressure, FIG. 5 illustrates the same section when subject to nodeforr'nation and before the projectile has been inserted in the gun.. PEG. 6 exemplifies the approximate deformation of the same '0 ring due to it having been inserted in a gun, although the space between the projectile and gun is somewhat exaggerated in FIGS. .4 and 6.

caseless propellant, a primer in a rear portion of said closure for translating said rod and causing it to impinge upon said primer. I 7

3. A combination according to claim 1 in which said packing ring is one of a-pair of 0 rings carried on the outside of said second projectile.

4. A combination according toclaim 1 in which first mentioned projectile also has a packing on'its periphery 15 and a firing rod axially through it;

References Cited by the Examiner UNITED STATES PATENTS Rupertus 102-38 210,374 11/78 Trabue ,102-,-38

657,248 9/00 Phillips 102-93 895,558 8/08 Harris 10,2--43 1,313,875 2 19 Borel 102-40 X 1,455,354 5/23 Porter 102-93 2,099,993 11/37 Tauschek 42- 69 X 2,356,227 8/44 Diehl 102' 92.5 2,790,353 4/57 Bird 42-39.5 X 3,008,258 11/61 Iohnson 42 14 BENJAMIN A. BORCHELT, Primary Examiner. 

1. IN A CLOSED BREECH FIREARM FOR FIRING A CASELESS ROUND OF PROPELLANT, THE COMBINATION THEREWITH OF A BREECH CLOSURE, A GUN BARREL EXTENDING AXIALLY FORWARDLY FROM SAID BREECH CLOSURE, A PROJECTILE TO BE FIRED FROM SAID BARREL, A CASELESS ROUND OF PROPELLANT IN REAR OF SAID PROJECTILE TO BE FIRED, AND A SECOND PROJECTILE IN REAR OF SAID CASELESS PROPELLANT, A PRIMER IN A REAR PORTION OF SAID PROPELLANT, A FIRING ROD EXTENDING THROUGH SAID SECOND PROJECTILE AXIALLY THEREOF TO ADJACENT SAID PRIMER, MEANS FOR TRANSMITTING ENERGY FOR FIRING SAID PRIMER THROUGH SAID FIRING ROD, AND A PACKING RING ON THE PRIPHERY OF SAID SECOND PROJECTILE. 